Wear particles are phagocytosed by macrophages and other inflammatory cells,
resulting in cellular activation and release of proinflammatory factors, which
cause periprosthetic osteolysis and subsequent aseptic loosening, the most
common causes of total joint arthroplasty failure. During this pathological
process, tumor necrosis factor-alpha (TNF-α) plays an important role in
wear-particle-induced osteolysis. In this study, recombination adenovirus (Ad)
vectors carrying both target genes [TNF-α small interfering RNA (TNF-α-siRNA)
and bone morphogenetic protein 2 (BMP-2)] were synthesized and transfected into
RAW264.7 macrophages and pro-osteoblastic MC3T3-E1 cells, respectively. The
target gene BMP-2, expressed on pro-osteoblastic MC3T3-E1 cells and silenced by
the TNF-α gene on cells, was treated with titanium (Ti) particles that were
assessed by real-time PCR and Western blot. We showed that recombinant
adenovirus (Ad-siTNFα-BMP-2) can induce osteoblast differentiation when treated
with conditioned medium (CM) containing RAW264.7 macrophages challenged with a
combination of Ti particles and Ad-siTNFα-BMP-2 (Ti-ad CM) assessed by alkaline
phosphatase activity. The receptor activator of nuclear factor-κB ligand was
downregulated in pro-osteoblastic MC3T3-E1 cells treated with Ti-ad CM in
comparison with conditioned medium of RAW264.7 macrophages challenged with Ti
particles (Ti CM). We suggest that Ad-siTNFα-BMP-2 induced osteoblast
differentiation and inhibited osteoclastogenesis on a cell model of a Ti
particle-induced inflammatory response, which may provide a novel approach for
the treatment of periprosthetic osteolysis.